>Later, during the 1920s and 1930s, Italian fascists and Nazi Germans adopted a salute which was very similar, which they attributed to the so-called Roman salute, a gesture that is wrongly thought to have been used in ancient Rome. This resulted in controversy over the use of the Bellamy salute in the United States. It was officially replaced by the hand-over-heart salute when Congress amended the Flag Code on December 22, 1942.

In other words, when people decided "fuck that, I dont want to look like a Nazi" they did something different.

Which is precisely why what Musk did was a Nazi salute. Because we know not to do them for fear of being mistaken for a Nazi. The deniability is implausible at this stage.